聚驱后提高采收率及注入参数优化实验研究

Experimental Study on the Method of Improving Recovery and Optimization of Injection Parameters after Polymer Flooding

目前,渤海L油田已经进入Cr^3+聚合物凝胶调驱(聚驱)调整阶段,亟待寻求聚驱后进一步提高采收率方法。针对矿场实际需求,开展了聚驱后提高采收率方法及其注入参数优化物理模拟研究。结果表明,与“高分”高质量浓度聚合物溶液、抗盐聚合物溶液、“聚合物/表面活性剂”二元体系和“碱/表面活性剂/聚合物”三元体系相比较,聚驱后Cr^3+聚合物凝胶调驱采收率增幅有较大提高,技术经济效果较好。随调驱剂注入段塞尺寸增加,采收率增幅呈现“先增后降”变化趋势,注入段塞尺寸为0.2PV时,“产出/投入”比最大。在调驱剂段塞尺寸相同条件下,与整体段塞相比较,采用“Cr^3+聚合物凝胶+水+聚合物溶液+水”或“Cr^3+聚合物凝胶+水”交替注入方式采收率增幅较大,表明该注入方式可以减缓“吸液剖面反转”进程,进一步提高中低渗透层波及系数。

At present,Bohai L oilfield has entered the adjustment stage of Cr^3+ polymer gel flooding ("polymer flooding").It is urgent to search for further EOR method after polymer flooding.In view of the actual demand of the oil field,the physical simulation research on the method of improving the recovery rate after the polymer flooding and the optimization of the injection parameters are studied in this paper.The result shows that compared with the" high molecular weight " high concentration polymer solution,the salt resistant polymer solution,"polymer/surfactant" two element system and "alkali/surfactant/polymer" three element system,the increase in recovery rate of Cr^3+ polymer gel flooding is larger after polymer flooding,and the technical and economic effect is better.with the increase of the size of the slug injected into the plug,the increase of the recovery rate shows a trend of "first increase and then decrease".When the size of the injected plug is 0.2 PV,the ratio of "output/input"is the largest.Under the conditions of the same size of flooding agent slug,compared with the whole slug,the recovery rate of "Cr^3+ polymer gel + water + polymer solution + water" or "Cr^3+ polymer gel + water" alternate injection increased greatly,showing that the injection mode can slow down the process of "suction profile inversion" and further improve the wave sum coefficient of low and medium permeability layers.